In the Linux kernel, the following vulnerability has been resolved:
erspan: make sure erspan_base_hdr is present in skb->head
syzbot reported a problem in ip6erspan_rcv() [1]
Issue is that ip6erspan_rcv() (and erspan_rcv()) no longer make
sure erspan_base_hdr is present in skb linear part (skb->head)
before getting @ver field from it.
Add the missing pskb_may_pull() calls.
v2: Reload iph pointer in erspan_rcv() after pskb_may_pull()
because skb->head might have changed.
[1]
BUG: KMSAN: uninit-value in pskb_may_pull_reason include/linux/skbuff.h:2742 [inline]
BUG: KMSAN: uninit-value in pskb_may_pull include/linux/skbuff.h:2756 [inline]
BUG: KMSAN: uninit-value in ip6erspan_rcv net/ipv6/ip6_gre.c:541 [inline]
BUG: KMSAN: uninit-value in gre_rcv+0x11f8/0x1930 net/ipv6/ip6_gre.c:610
pskb_may_pull_reason include/linux/skbuff.h:2742 [inline]
pskb_may_pull include/linux/skbuff.h:2756 [inline]
ip6erspan_rcv net/ipv6/ip6_gre.c:541 [inline]
gre_rcv+0x11f8/0x1930 net/ipv6/ip6_gre.c:610
ip6_protocol_deliver_rcu+0x1d4c/0x2ca0 net/ipv6/ip6_input.c:438
ip6_input_finish net/ipv6/ip6_input.c:483 [inline]
NF_HOOK include/linux/netfilter.h:314 [inline]
ip6_input+0x15d/0x430 net/ipv6/ip6_input.c:492
ip6_mc_input+0xa7e/0xc80 net/ipv6/ip6_input.c:586
dst_input include/net/dst.h:460 [inline]
ip6_rcv_finish+0x955/0x970 net/ipv6/ip6_input.c:79
NF_HOOK include/linux/netfilter.h:314 [inline]
ipv6_rcv+0xde/0x390 net/ipv6/ip6_input.c:310
__netif_receive_skb_one_core net/core/dev.c:5538 [inline]
__netif_receive_skb+0x1da/0xa00 net/core/dev.c:5652
netif_receive_skb_internal net/core/dev.c:5738 [inline]
netif_receive_skb+0x58/0x660 net/core/dev.c:5798
tun_rx_batched+0x3ee/0x980 drivers/net/tun.c:1549
tun_get_user+0x5566/0x69e0 drivers/net/tun.c:2002
tun_chr_write_iter+0x3af/0x5d0 drivers/net/tun.c:2048
call_write_iter include/linux/fs.h:2108 [inline]
new_sync_write fs/read_write.c:497 [inline]
vfs_write+0xb63/0x1520 fs/read_write.c:590
ksys_write+0x20f/0x4c0 fs/read_write.c:643
__do_sys_write fs/read_write.c:655 [inline]
__se_sys_write fs/read_write.c:652 [inline]
__x64_sys_write+0x93/0xe0 fs/read_write.c:652
do_syscall_64+0xd5/0x1f0
entry_SYSCALL_64_after_hwframe+0x6d/0x75
Uninit was created at:
slab_post_alloc_hook mm/slub.c:3804 [inline]
slab_alloc_node mm/slub.c:3845 [inline]
kmem_cache_alloc_node+0x613/0xc50 mm/slub.c:3888
kmalloc_reserve+0x13d/0x4a0 net/core/skbuff.c:577
__alloc_skb+0x35b/0x7a0 net/core/skbuff.c:668
alloc_skb include/linux/skbuff.h:1318 [inline]
alloc_skb_with_frags+0xc8/0xbf0 net/core/skbuff.c:6504
sock_alloc_send_pskb+0xa81/0xbf0 net/core/sock.c:2795
tun_alloc_skb drivers/net/tun.c:1525 [inline]
tun_get_user+0x209a/0x69e0 drivers/net/tun.c:1846
tun_chr_write_iter+0x3af/0x5d0 drivers/net/tun.c:2048
call_write_iter include/linux/fs.h:2108 [inline]
new_sync_write fs/read_write.c:497 [inline]
vfs_write+0xb63/0x1520 fs/read_write.c:590
ksys_write+0x20f/0x4c0 fs/read_write.c:643
__do_sys_write fs/read_write.c:655 [inline]
__se_sys_write fs/read_write.c:652 [inline]
__x64_sys_write+0x93/0xe0 fs/read_write.c:652
do_syscall_64+0xd5/0x1f0
entry_SYSCALL_64_after_hwframe+0x6d/0x75
CPU: 1 PID: 5045 Comm: syz-executor114 Not tainted 6.9.0-rc1-syzkaller-00021-g962490525cff #0
[
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "0a198e0bb8be",
"lessThan": "06a939f72a24",
"versionType": "git"
},
{
"status": "affected",
"version": "cb73ee40b1b3",
"lessThan": "e54a0c79cdc2",
"versionType": "git"
},
{
"status": "affected",
"version": "cb73ee40b1b3",
"lessThan": "b14b9f9503ec",
"versionType": "git"
},
{
"status": "affected",
"version": "cb73ee40b1b3",
"lessThan": "ee0088101bee",
"versionType": "git"
},
{
"status": "affected",
"version": "cb73ee40b1b3",
"lessThan": "1db7fcb2b290",
"versionType": "git"
},
{
"status": "affected",
"version": "cb73ee40b1b3",
"lessThan": "4e3fdeecec57",
"versionType": "git"
},
{
"status": "affected",
"version": "cb73ee40b1b3",
"lessThan": "0ac328a5a413",
"versionType": "git"
},
{
"status": "affected",
"version": "cb73ee40b1b3",
"lessThan": "17af420545a7",
"versionType": "git"
}
],
"programFiles": [
"net/ipv4/ip_gre.c",
"net/ipv6/ip6_gre.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "5.0"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "5.0",
"versionType": "custom"
},
{
"status": "unaffected",
"version": "4.19.312",
"versionType": "custom",
"lessThanOrEqual": "4.19.*"
},
{
"status": "unaffected",
"version": "5.4.274",
"versionType": "custom",
"lessThanOrEqual": "5.4.*"
},
{
"status": "unaffected",
"version": "5.10.215",
"versionType": "custom",
"lessThanOrEqual": "5.10.*"
},
{
"status": "unaffected",
"version": "5.15.154",
"versionType": "custom",
"lessThanOrEqual": "5.15.*"
},
{
"status": "unaffected",
"version": "6.1.85",
"versionType": "custom",
"lessThanOrEqual": "6.1.*"
},
{
"status": "unaffected",
"version": "6.6.26",
"versionType": "custom",
"lessThanOrEqual": "6.6.*"
},
{
"status": "unaffected",
"version": "6.8.5",
"versionType": "custom",
"lessThanOrEqual": "6.8.*"
},
{
"status": "unaffected",
"version": "6.9",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"net/ipv4/ip_gre.c",
"net/ipv6/ip6_gre.c"
],
"defaultStatus": "affected"
}
]
git.kernel.org/stable/c/06a939f72a24a7d8251f84cf4c042df86c6666ac
git.kernel.org/stable/c/0ac328a5a4138a6c03dfc3f46017bd5c19167446
git.kernel.org/stable/c/17af420545a750f763025149fa7b833a4fc8b8f0
git.kernel.org/stable/c/1db7fcb2b290c47c202b79528824f119fa28937d
git.kernel.org/stable/c/4e3fdeecec5707678b0d1f18c259dadb97262e9d
git.kernel.org/stable/c/b14b9f9503ec823ca75be766dcaeff4f0bfeca85
git.kernel.org/stable/c/e54a0c79cdc2548729dd7e2e468b08c5af4d0df5
git.kernel.org/stable/c/ee0088101beee10fa809716d6245d915b09c37c7
lists.debian.org/debian-lts-announce/2024/06/msg00017.html
lists.debian.org/debian-lts-announce/2024/06/msg00020.html